Hawaii facing major impacts from global climate change
KAUAʻI—Increased flooding, coastal erosion, rising sea levels, dissolving coral reefs and more extreme rainfall events are expected to be the local results of the global warming that many scientists agree is already under way.
Nearly 200 people gathered at a conference on Kauaʻi this past weekend to learn from local scientists what is known about global climate change and how it’s likely to affect the Hawaiian Islands.
“No community is going to be exempt from the effects of global climate change,” said James O’Connell of the University of Hawaiʻi Sea Grant College Program. “It’s not just the potential, it’s happening already. It’s documented.”
Dr. Chip Fletcher, a professor with the UH Geology & Geophysics Department, said that he was a denier and skeptic in the 1990s because the evidence wasn’t compelling. But since then, he’s come on board, along with most of the world’s scientists.
It’s clear, Fletcher said, that the CO2 level is at its highest in 15 million years. Meanwhile, the rate of loss in the world’s ice mass is accelerating and the sea level has risen to the point where it’s “changing lives” in some low-lying islands in Micronesia.
In Hawaiʻi, he said, salt water is already oozing into the streets of Waikiki at high tide.
Fletcher expects the sea level to rise about 1 meter by the end of the century, and for Hawaiʻi that means problems with drainage. As the sea level rises, it will take less rainfall to trigger flooding, especially in coastal communities that are backed by wetlands, like Hanalei, Kapaʻa, and Wailua.
At the same time, “our big waves will punch further into the coastal plains,” he said. “Dramatic flooding will occur and will increase in intensity and frequency.”
Erosion is also increasing in some areas where there’s no calcium carbonate to replenish the sand stripped away by storms. “We’ll be saying aloha to a lot of our nice sandy beaches here,” he said.
Dr. Paul Jokiel of the University’s Hawaiʻi Institute of Marine Biology said warmer temperatures and the increased acidification of the ocean caused by rising CO2 levels spell trouble for Hawaiʻi’s coral reefs.
Major bleaching incidents already have been reported in Hawaiʻi’s coral reefs, most recently in the Northwestern Hawaiian Islands, he said, and such occurrences will increase in a warmer, more acidic ocean. The same factors also can work to hinder the ability of coral organisms to calcify.
“We’re going into something geologically new of having our reefs dissolve as we go through this century,” Jokiel said. And that has serious implications for ocean ecosystems, fishing, recreation and the storm protection that reefs provide.
It’s less clear how global warming may affect rainfall in Hawaiʻi, said Dr. Tom Giambelluca, a UH geography professor.
He presented evidence that the Islands are warming, especially at higher elevations, which spells trouble for the endangered forest birds and plants that are struggling to survive there, and also at night, which similarly disrupts ecosystems and biological processes.
Giambelluca said it’s also apparent that Hawaiʻi is experiencing a significant decrease in winter rainfall, which Dr. Gordon Tribble, a U.S. Geological Survey stream flow expert, said has contributed to a reduction in the Islands’ base stream flow. This, in turn, has implications for water availability and agriculture.
But both Tribble and Giambelluca said they still don’t know if the trends they are seeing are caused by global warming, or part of a natural cycle.
“We’re pretty confident it’s going to get warmer, but not as confident about what’s going to happen to our rainfall,” Giambelluca said, although it appears the Islands may get warmer and drier, with severe events producing the bulk of the rainfall.
“We have to start looking at what crops can grow with very little water, and how hydroelectric plants will be affected by lower stream flows,” said Dr. Carl Berg, who organized the event on behalf of Surfrider Foundation Kauaʻi and Kauaʻi Community College.
Jokiel said he didn’t want to deliver a doom-and-gloom talk without giving folks both hope and concrete measures that could reduce CO2 levels and slow global warming. These include eating less meat, adopting alternative energies, painting roofs white and other simple steps.
While some of these measures are expensive, Jokiel said, they pale in comparison to the money spent bailing out our financial institutions, which he pegged at about $8.9 trillion.
“We’re just going to have to get it together and do the equivalent of building the interstate or sending a man to the moon,” Jokiel said. “I see it as a great opportunity to bring our civilization to a level that’s sustainable.”
Fletcher is currently working to map the Hawaiian Islands to show the impact of an anticipated 1 meter sea level rise. This link shows Kauaiʻs coast under such a scenario. The Oʻahu map should be completed next year.